I have the microfilm for Fort Steilacom back to late 1849. An invaluable glimpse of our little ice age climate. The 1860s and 1880s were actually more exciting than the 1850s. I actually have those Fort Steilacom records digitized now.
People need to remember the ECMWF seems to have a very wet bias for the Puget Sound region, and climo highly argues against anything near what it's showing. It would be the equivalent of a good 8 to 10 inch snow dump for SEA for rarity.
Not this time of year. It's almost impossible for something like what's being shown to verify this time of year. It might, but it could still fall flat on it's face.